How to install NextGEN Facebook - Advanced Social SEO for Facebook, Google+, Pinterest, Twitter & More plugin:
Go to Wordpress admin area and click "Plugins" and then "Add New" menu item.
In the right panel (left top) you will see "Upload Plugin" button. Click the button.
Next click the "Choose file" button in right panel (center).
Select zip file of the "NextGEN Facebook - Advanced Social SEO for Facebook, Google+, Pinterest, Twitter & More" plugin located on your hard drive and press "Open".
Click "Install Now" and the zip file will upload to your site.
Now click "Activate" button to activate the "NextGEN Facebook - Advanced Social SEO for Facebook, Google+, Pinterest, Twitter & More" plugin.
We've tested following plugins published by: Jean-Sebastien Morisset